This invention relates to means for connecting a spare transformer to a 3-phase electric bus to provide for replacement of any one of three single phase transformers normally connected in delta to the bus.
It sometimes becomes necessary to replace one of the single phase transformers of such a system to permit repairs or other work to be performed on the transformer. The usual procedure for effecting this replacement is to disconnect and physically remove the deficient transformer and to physically move into the vacant location a spare transformer and then to connect the spare to the bus. Since these transformers can be quite massive, it will be apparent that this can be a time-consuming and expensive operation, particularly when it is realized that the power system must be shut down during this operation.